Electrical machine

Abstract

An electrical pump or generator apparatus comprises a sealed housing having fluid inlet and outlet ports and an impeller rotatably mounted inside a cavity of the housing, the impeller being mounted on a shaft for rotation about an axis, the shaft being confined inside the sealed housing. An electric machine of the pump has a stator disposed outside the housing and a rotor sealed inside the housing. In use a rotating magnetic field extends through a boundary wall of the housing to magnetically couple the stator and rotor on opposite sides of thereof. The need for a shaft seal is thus avoided and the apparatus is more compact than conventional pumps and generators.

1 . An electrical pump comprising a housing having fluid inlet and outlet ports and an impeller rotatably mounted inside a cavity of a sealed housing for causing a flow of liquid from the inlet to the outlet port upon rotation thereof, the impeller being mounted on a shaft for rotation about an axis, the shaft being confined inside the sealed housing, the pump further comprising an electric motor having a stator disposed outside the housing and a rotor sealed inside the housing on said shaft, the stator having an electrical coil which, when energised, causes a rotating magnetic field to be radiated through a boundary wall of the housing to induce rotation of the stator and hence the impeller about said axis. 
     
     
         2 . (canceled) 
     
     
         3 . An electrical pump as claimed in  claim 1 , in which the rotor comprises an annular array of circumferentially spaced permanent magnets. 
     
     
         4 . (canceled) 
     
     
         5 . (canceled) 
     
     
         6 . An electrical pump as claimed in  claim 3 , in which the poles of adjacent magnets are opposite. 
     
     
         7 . An electrical pump as claimed in  claim 3 , in which the poles of adjacent magnets are in Halbach arrangement. 
     
     
         8 . An electrical pump as claimed in  claim 1 , in which a ferromagnetic member having a low reluctance path is disposed on the opposite side of the stator to the rotor or vice-versa. 
     
     
         9 . An electrical pump as claimed in  claim 1 , in which a rotary coupling member is disposed external of the housing between the stator and the rotor, an axis of rotation of the coupling member being colinear with an rotor axis. 
     
     
         10 . An electrical pump as claimed in  claim 9 , in which the coupling member comprises an annular array of circumferentially spaced permanent magnets. 
     
     
         11 . An electrical pump as claimed in  claim 10 , in which the magnets of the coupling member and rotor each have poles which face axially, the poles of adjacent magnets being opposite. 
     
     
         12 . An electrical pump as claimed in  claim 10 , in which the magnets of the coupling member and rotor each have poles which face axially, the poles of adjacent magnets being in a Halbach arrangement. 
     
     
         13 . (canceled) 
     
     
         14 . An electrical generator apparatus comprising a housing having fluid inlet and outlet ports and an impeller rotatably mounted inside a cavity of a sealed housing and arranged to rotate upon fluid flow through the housing from the inlet to the outlet port, the impeller being mounted on a shaft for rotation about an axis, the shaft being confined inside the sealed housing, the apparatus further comprising an electric generator having a stator disposed outside the housing and a rotor sealed inside the housing on said shaft, the rotor comprising a magnet which radiates a magnetic field through a boundary wall of the housing and which induces electrical current in a coil of the stator when the impeller is rotated about said axis. 
     
     
         15 . (canceled) 
     
     
         16 . An electrical generator apparatus as claimed in  claim 14 , in which the rotor comprises an annular array of circumferentially spaced permanent magnets. 
     
     
         17 . (canceled) 
     
     
         18 . (canceled) 
     
     
         19 . An electrical generator apparatus as claimed in  claim 16 , in which the poles of adjacent magnets are opposite. 
     
     
         20 . An electrical generator apparatus as claimed in  claim 16 , in which the poles of adjacent magnets are in Halbach arrangement. 
     
     
         21 . An electrical generator apparatus as claimed in  claim 14 , in which a ferromagnetic member having a low reluctance path is disposed on the opposite side of the stator to the rotor or vice-versa. 
     
     
         22 . An electrical generator apparatus as claimed in  claim 14 , in which a rotary coupling member is disposed external of the housing between the stator and the rotor, an axis of rotation of the coupling member being colinear with a rotor axis. 
     
     
         23 . An electrical generator apparatus as claimed in  claim 22 , in which the coupling member comprises an annular array of circumferentially spaced permanent magnets. 
     
     
         24 . An electrical generator apparatus as claimed in  claim 23 , in which the magnets of the coupling member and rotor each have poles which face axially, the poles of adjacent magnets being opposite. 
     
     
         25 . An electrical generator apparatus as claimed in  claim 23 , in which the magnets of the coupling member and rotor each have poles which face axially, the poles of adjacent magnets being in a Halbach arrangement. 
     
     
         26 . (canceled) 
     
     
         27 . An electrical apparatus comprising a housing for sealingly containing a fluid and having fluid inlet and outlet ports and an impeller rotatably mounted inside a cavity of the housing and arranged to rotate, the impeller being mounted on a shaft for rotation about an axis, the shaft being confined inside the sealed housing, the apparatus further comprising an electrical machine having a stator disposed outside the housing and a rotor sealed inside the housing on said shaft, the rotor comprising a magnet, the apparatus being arranged such that in use a rotating magnetic field extends through a boundary wall of the housing to magnetically couple the stator and rotor on opposite sides thereof. 
     
     
         28 . (canceled) 
     
     
         29 . An electrical apparatus as claimed in  claim 27 , in which the apparatus is a electrical generator apparatus and the electrical machine is a generator, the rotor inducing an electrical current in a coil of the stator when the impeller is rotated about said axis.